using System;

using System.Collections.Generic;

using System.Linq;

using System.Web.Http;

using System.Web.Http.Dispatcher;

namespace WebApi多版本控制1

{

    public static class WebApiConfig

    {

        public static void Register(HttpConfiguration config)

        {

            // Web API 配置和服务

            // Web API 路由

            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(

                name: "DefaultApiV1",

                routeTemplate: "api/v1/{controller}/{id}",

                defaults: new { id = RouteParameter.Optional }

            );

            config.Routes.MapHttpRoute(

            name: "DefaultApiV2",

            routeTemplate: "api/v2/{controller}/{id}",

            defaults: new { id = RouteParameter.Optional }

        );

            config.Services.Replace(typeof(IHttpControllerSelector), new VersionControllerSelector(config));

        }

    }

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net.Http;

using System.Text.RegularExpressions;

using System.Web;

using System.Web.Http;

using System.Web.Http.Controllers;

using System.Web.Http.Dispatcher;

namespace WebApi多版本控制1

{

    public class VersionControllerSelector:DefaultHttpControllerSelector

    {

        private HttpConfiguration config;

        private IDictionary<string, HttpControllerDescriptor> ctlMapping;

        public VersionControllerSelector(HttpConfiguration config ):base(config)

        {

            this.config = config;

        }

        public override IDictionary<string, HttpControllerDescriptor> GetControllerMapping()

        {

            Dictionary<string, HttpControllerDescriptor> dict = new Dictionary<string, HttpControllerDescriptor>();

            foreach (var asm in config.Services.GetAssembliesResolver().GetAssemblies())

            {

              var controllerTypes=  asm.GetTypes().Where(t => t.IsAbstract == false && typeof(ApiController).IsAssignableFrom(t));

                foreach (var ctrlType in controllerTypes)

                {

                  string ctrlTypeNS=  ctrlType.Namespace ;

                  var match=   Regex.Match(ctrlTypeNS, @"\.v(\d)");

                    if (!match.Success)

                    {

                        continue;

                    }

                        string verNum = match.Groups[].Value;//把版本号1提取除了

                        string ctrlTypeName = ctrlType.Name;//PersonController

                        var matchControler = Regex.Match(ctrlTypeName, "^(.+)Controller$");

                        if (!matchControler.Success)

                        {

                        continue;

                        }

                    string ctrlName = matchControler.Groups[].Value;

                    string key = ctrlName + "v" + verNum;//Personv1

                    dict[key] = new HttpControllerDescriptor(config, ctrlName, ctrlType);

                }

            }

            ctlMapping = dict;

            return dict;

        }

        public override HttpControllerDescriptor SelectController(HttpRequestMessage request)

        {

            string controller=  (string)  request.GetRouteData().Values["controller"];

            if (ctlMapping==null)

            {

                ctlMapping = GetControllerMapping();

            }

            var matchVer = Regex.Match(request.RequestUri.PathAndQuery, @"/v(\d+)/");

            if (!matchVer.Success)

            {

                return base.SelectController(request);

            }

            string verNum = matchVer.Groups[].Value;

            string key = controller + "v" + verNum;

            if (ctlMapping.ContainsKey(key))

            {

                return ctlMapping[key];

            }

            else

            {

                return base.SelectController(request);

            }

        }

    }

}